Long-term survival following additive radiotherapy in patients with atypical teratoid rhabdoid tumors.

BACKGROUND: Atypical teratoid rhabdoid tumor (ATRT) is a highly aggressive disease of embryonic origin accounting for <5% of all pediatric central nervous system (CNS) tumors. PATIENTS AND METHODS: We describe a series of five cases of CNS ATRT. The first three patients underwent subtotal tumor resection. Gross total resection of the tumor was achieved in the fourth and fifth patients. Only 4 patients received chemotherapy, whereas all 5 patients received additive radiotherapy (RT). The latter included three dimensional (3D) conformal RT or intensity modulated RT (IMRT) with a median dose of 54 Gy (range 50.4-59.0 Gy) applied in daily fractions of 1.8 Gy. The median interval between surgery and RT was 5 months (range 2-11 months). RESULTS: Two months after completion of RT, 4 patients had achieved complete radiologic remission. The median event-free survival period was 46 months (range 10-90 months). However, the first patient died 17 months after developing an out-of-field recurrence. The third patient developed a recurrence 11 months after salvage RT. The other 3 patients (cases 2, 4, and 5) remain alive with no evidence of disease 59, 46 and 90 months after therapy, respectively. CONCLUSION: Overall, the 5 patients survived for a median of 48 months (range 25-90 months) from the time of initial diagnosis and they tolerated the RT well, without severe acute or late onset toxicities. The results imply a potential survival gain after irradiation at acceptable toxicity level.

Impact of Adjuvant Radiotherapy in Patients with Central Neurocytoma: A Multicentric International Analysis.

BACKGROUND: Central neurocytoma (CN) is a rare tumor accounting for <0.5% of all intracranial tumors. Surgery ± radiotherapy is the mainstay treatment. This international multicentric study aims to evaluate the outcomes of CNs patients after multimodal therapies and identify predictive factors. PATIENTS AND METHODS: We retrospectively identified 33 patients with CN treated between 2005 and 2019. Treatment characteristics and outcomes were assessed. RESULTS: All patients with CN underwent surgical resection. Radiotherapy was delivered in 19 patients. The median radiation dose was 54 Gy (range, 50-60 Gy). The median follow-up time was 56 months. The 5-year OS and 5-year PFS were 90% and 76%, respectively. Patients who received radiotherapy had a significantly longer PFS than patients without RT (p = 0.004) and a trend towards longer OS. In addition, complete response after treatments was associated with longer PFS (p = 0.07). CONCLUSIONS: Using RT seems to be associated with longer survival rates with an acceptable toxicity profile.

The Role of Radiotherapy for Patients With Thyroid Cancer in the Modern Era.

BACKGROUND/AIM: Thyroid cancer (TC) is a relatively rare malignancy. The mainstay treatment is surgery followed by radioactive iodine (RAI) and medical systemic treatments. The role of external beam radiotherapy (EBRT) in TC is controversial regarding the survival benefits. The aim of this study was to analyse the effectiveness of EBRT for different forms of TC in different stages. PATIENTS AND METHODS: Between January 1990 and 2016, 75 patients underwent 255 radiotherapy (RT) courses at our Institution. Local control (LC) and progression-free survival (PFS) were analyzed. RESULTS: The cohort consisted of 22 patients who received curative RT and 53 patients who received RT in a palliative setting. The estimated 5-year LC for the curative group was 92±8% and the palliative group 78±7%. The estimated 5-year PFS for the curative group was 27±9% and for palliative group 31±6%. CONCLUSION: The addition of RT in TC seems to be safe and effective. Our analysis showed an excellent local control (median >15 years) regardless of the treatment setting.

A treatment planning study comparing IMRT techniques and cyber knife for stereotactic body radiotherapy of low-risk prostate carcinoma.

PURPOSE: Comparing radiation treatment plans by using the same safety margins and dose objectives for all techniques, to ascertain the optimal radiation technique for the stereotactic body radiotherapy (SBRT) of low-risk prostate cancer. MATERIAL AND METHODS: Treatment plans for 27 randomly selected patients were compared using intensity-modulated (IMRT) techniques as Sliding Window (SW), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT), as well as Cyber Knife (CK) system. The target dose was calculated to 36.25 Gy delivered in five fractions over 1 week. Dosimetric indices for target volume and organs at risk (OAR) as well as normal tissue complication probability (NTCP) of late rectal and urinary bladder toxicities were analyzed. RESULTS: The CK provided lower homogeneity in the target volume, but higher values for most of the conformity indices compared to the IMRT approaches. The SW demonstrated superior rectum sparing at medium-to-high dose range (V18 Gy - V32.6 Gy) compared to other techniques (p < 0.05). The whole urinary bladder experienced the best shielding by SW and VMAT at the medium dose (V18 Gy, p < 0.05 versus CK), however we obtained no relevant differences between techniques at the high dose. Generally, the CK demonstrated significantly superior rectum and bladder exposure at V18 Gy as compared to HT, SW, and VMAT. For the rectum, mean NTCP values were significantly superior for HT (NTCP = 2.3%, p < 0.05), and for urinary bladder, the NTCP showed no significant advantages for any technique. CONCLUSION: No absolute dosimetric advantage was revealed to choose between CK or IMRT techniques for the SBRT of low-grade prostate cancer. Using the same safety margins and dose objectives, IMRT techniques demonstrated superior sparing of the rectum and bladder at a medium dose compared to CK. Comparing different IMRT approaches SW displayed superior rectum sparing at a medium-to-high dose range, whereas both SW and RA revealed superior bladder sparing compared to HT. HT demonstrated a significantly lower NTCP outcome compared to CK or IMRT techniques regarding the rectum. Radiation plans can be optimized further by an individual modification of dose objectives independent of the treatment plan strategy.

Is tumor volume reduction during radiotherapy prognostic relevant in patients with stage III non-small cell lung cancer?

PURPOSE/OBJECTIVE(S): Lung cancer tumor volume reduction is common during radiation treatment (RT). The purpose of this study was to investigate tumor volume reduction ratio (VRR) and its correlation with outcomes in a cohort of patients with stage III non-small cell lung cancer (NSCLC) who underwent image-guided radiochemotherapy (RCTx). MATERIALS/METHODS: Fifty patients with NSCLC treated with fractionated RT at our institution between 2013 and 2017 were included. The relationship between gross tumor volume (GTV) changes during RT (week 1 vs. week 5) and outcomes were evaluated. RESULTS: The median radiation dose delivered was 59.4 Gy (median fraction dose, 1.8 Gy). The median GTV before treatment was 119 cm3, with a median GTV change of - 40%. Patients with more volume reduction had poorer tumor control. A VRR > 40% was associated with a poorer OS and PFS in patients with non-adenocarcinoma (non-ADC) histology. In multivariate analysis, VRR during RT, and chemotherapy (CTx) administration remained related to PFS and OS, while initial GTV remained a significant determinant for OS. In subgroup analyses, and CTx (p = 0.038) affected PFS among non-ADC patients, with initial GTV (p = 0.058) and VRR (p = 0.08) showing non-significant trends. Initial GTV (p = 0.023), VRR (p = 0.038), and CTx (p = 0.01) remained significant predictors for OS in the non-ADC group. CONCLUSION: Worse tumor control and OS in non-ADC patients are observed with more marked RT-induced tumor shrinkage, supporting the development of response-adaptive treatment strategies, particularly in non-ADC NSCLC patients.